A potential therapeutic drug for osteoporosis: prospect for osteogenic LncRNAs.

Long non-coding RNAs (LncRNAs) play essential roles in multiple physiological processes including bone formation. Investigators have revealed that LncRNAs regulated bone formation through various signaling pathways and micro RNAs (miRNAs). However, several problems exist in current research studies on osteogenic LncRNAs, including sophisticated techniques, high cost for in vivo experiment, as well as low homology of LncRNAs between animal model and human, which hindered translational medicine research. Moreover, compared with gene editing, LncRNAs would only lead to inhibition of target genes rather than completely knocking them out. As the studies on osteogenic LncRNA gradually proceed, some of these problems have turned osteogenic LncRNA research studies into slump. This review described some new techniques and innovative ideas to address these problems. Although investigations on osteogenic LncRNAs still have obtacles to overcome, LncRNA will work as a promising therapeutic drug for osteoporosis in the near future.

Inactivation and process intensification of ß-glucosidase in biomass utilization.

Lignocellulosic biomass has emerged as a promising environmental resource. Enzyme catalysis, as one of the most environmentally friendly and efficient tools among various treatments, is used for the conversion of biomass into chemicals and fuels. Cellulase is a complex enzyme composed of ß-glucosidase (BGL), endo-ß-1,4-glucanase (EG), and exo-ß-1,4-glucanase (CBH), which synergistically hydrolyzes cellulose into monosaccharides. BGL, which further deconstructs cellobiose and short-chain cellooligosaccharides obtained by EG and CBH catalysis into glucose, is the most sensitive component of the synergistic enzyme system constituted by the three enzymes and is highly susceptible to inactivation by external conditions, becoming the rate-limiting component in biomass conversion. This paper firstly introduces the source and catalytic mechanism of BGL used in the process of biomass resource utilization. The focus is on the review of various factors affecting BGL activity during hydrolysis, including competitive adsorption of lignin, gas-liquid interface inactivation, thermal inactivation, and solvent effect. And the methods to improve BGL inactivation are proposed from two aspects-substrate initiation and enzyme initiation. In particular, the screening, modification, and alteration of the enzyme molecules themselves are discussed with emphasis. This review can provide novel ideas for studies of BGL inactivation mechanism, containment of inactivation, and activity enhancement. KEY POINTS: • Factors affecting ß-glucosidase inactivation are described. • Process intensification is presented in terms of substrate and enzyme. • Solvent selection, protein engineering, and immobilization remain topics of interest.

Potassium modulates central carbon metabolism to participate in regulating CO2 transport and assimilation in Brassica napus leaves.

Potassium (K) regulates plant metabolism and enhances plant's ability to adapt to adversity. However, under different K deficiency stress, the net photosynthetic rate (An) was reduced, influenced by CO2 conductance or biochemical capacities. The interplay between metabolome and photosynthetic characteristics under K deficiency stress was analyzed to explore the mechanisms by which K regulates photosynthetic capacity. With increasing K deficiency stress, dominations limiting An varied from CO2 conductance to biochemical limitations. Multivariate analyses indicated that organic acids, amino acids and sedoheptulose-7-bisphosphate were significantly related to An, CO2 conductance and carboxylation rate. Under moderate K deficiency, organic acids were up-regulated. Acidification of subcellular compartments reduced sedoheptulose-1,7-bisphosphatase activity, inducing downregulation of sedoheptulose-7-bisphosphate and hindrance of ribulose bisphosphate regeneration. Moreover, increased CO2 shortage with increasing K deficiency induced a shift of increased citric acid to amino acid synthesis, causing excessive accumulation of amino acids. In addition, the reduced serine level indicated impaired photorespiration. These two changes triggered more serious reduction in photosynthetic capacity. The intimate, changes in photosynthetic capacities were tightly coupled with shifts in central C metabolism, which provides insights into the methods used to enhance An and plant's adaptability to abiotic stresses, through the regulation of C metabolites using molecular technology.

Isolation and characterization of PoWRKY, an abiotic stress-related WRKY transcription factor from Polygonatum odoratum.

WRKY transcription factors play vital roles in response to biotic and abiotic stresses in plants. As a kind of high value medicinal plant, Polygonatum odoratum has an ability to tolerate various abiotic stresses because of the special growth condition. In current study, a novel WRKY gene from P. odoratum is isolated and compared with homologous sequences from other plants. PoWRKY1 possesses two typical WRKY domains and two C2H2 zinc-finger motifs. Evolutionary analysis indicated that PoWRKY1 is most closely related to WRKY protein from Asparagus officinalis. Expression analysis showed that expression of PoWRKY1 is induced by cold and drought stresses but not salt stress. Overexpression of PoWRKY1 in Arabidopsis improved seed germination and root growth of transgenic plants during cold stress and drought. In addition, super oxide dismutase activity and proline content in transgenic plants increased under cold and drought stresses, whereas malondialdehyde levels and relative electrolyte leakage reduced under similar stress conditions. Taken together, these results showed that PoWRKY1 enhances the tolerance to cold and drought stresses. This study lays a potential foundation to understand the molecular mechanism of tolerance to abiotic stress in P. odoratum.

The reduction in leaf area precedes that in photosynthesis under potassium deficiency: the importance of leaf anatomy.

Synergistic improvement in leaf photosynthetic area and rate is essential for enhancing crop yield. However, reduction in leaf area occurs earlier than that in the photosynthetic rate under potassium (K) deficiency stress. The photosynthetic capacity and anatomical characteristics of oilseed rape (Brassica napus) leaves in different growth stages under different K levels were observed to clarify the mechanism regulating this process. Increased mesophyll cell size and palisade tissue thickness, in K-deficient leaves triggered significant enlargement of mesophyll cell area per transverse section width (S/W), in turn inhibiting leaf expansion. However, there was only a minor difference in chloroplast morphology, likely because of K redistribution from vacuole to chloroplast. As K stress increased, decreased mesophyll surface exposed to intercellular space and chloroplast density induced longer distances between neighbouring chloroplasts (Dchl-chl ) and decreased the chloroplast surface area exposed to intercellular space (Sc /S); conversely this induced a greater limitation imposed by the cytosol on CO2 transport, further reducing the photosynthetic rate. Changes in S/W associated with mesophyll cell morphology occurred earlier than changes in Sc /S and Dchl-chl , inducing a decrease in leaf area before photosynthetic rate reduction. Adequate K nutrition simultaneously increases photosynthetic area and rate, thus enhancing crop yield.

Leaf photosynthetic capacity is regulated by the interaction of nitrogen and potassium through coordination of CO2 diffusion and carboxylation.

Combined application of nitrogen (N) and potassium (K) fertilizer could significantly enhance crop yield. Crop yield and photosynthesis are inseparable. However, the influence of N and K interaction on photosynthesis is still not fully understood. Field and hydroponic experiments were conducted to examine the effects of N and K interaction on leaf photosynthesis characteristics and to explore the mechanisms in the hydroponic experiment. CO2 conductance and carboxylation characteristic parameters of oilseed leaves were measured under different N and K supplies. Results indicated that detectable increases in leaf area, biomass and net photosynthetic rate (An ) were observed under optimal N and K supply in field and hydroponic experiments. The ratio of total CO2 diffusion conductance to the maximum carboxylation rate (gtot /Vcmax ) and An presented a linear-plateau relationship. Under insufficient N, increased K contributed to the CO2 transmission capacity and improved the proportion of N used for carboxylation, promoting gtot /Vcmax . However, the low Vcmax associated with N insufficiency limited the An . High N supply obviously accelerated Vcmax , yet K deficiency led to a reduction of gtot , which restricted Vcmax . Synchronous increases in N and K supplementation ensured the appropriate ratio of N to K content in leaves, which simultaneously facilitated gtot and Vcmax and preserved a gtot /Vcmax suitable for guaranteeing CO2 transmission and carboxylation coordination; the overall effect was increased An and leaf area. These results highlight the suitable N and K nutrients to coordinate CO2 diffusion and carboxylation, thereby enhancing photosynthetic capacity and area to obtain high crop yield.

Poly[di-µ(3)-hy-droxy[µ(4)-5-(4-carb-oxy-phen-yl)pyridine-2-carboxyl-ato-κ(5)N,O(2):O(2'):O(4):O(4')]dicadmium].

The asymmetric unit of the title polymeric complex, [Cd(2)(C(13)H(7)NO(4))(OH)(2)](n), consists of two independent Cd(II) atoms, one 5-(4-carb-oxy-phen-yl)pyridine-2-carboxyl-ate ligand and two hy-droxy groups. One Cd(II) atom is six-coordinated by two O atoms from two ligand mol-ecules and by four µ(3)-OH groups in a distorted trigonal-prismatic geometry. The other is five-coordinated by one N and two O atoms from two ligands and by two µ(3)-OH groups, forming a distorted square-pyramidal geometry. The two independent Cd(II) atoms are connected by the ligand mol-ecules and the OH groups into a three-dimensional framework. O-H⋯O hydrogen bonds between the OH groups and the carboxyl-ate O atoms are observed.

catena-Poly[[dichloridozinc(II)]-µ-1,1'-(butane-1,4-di-yl)diimidazole-κN:N].

The title compound, [ZnCl(2)(C(10)H(14)N(4))](n), is a coordination polymer consisting of zigzag chains propagating in [001], in which the metal cation exhibits a distorted tetrahedral ZnCl(2)N(2) coordination. Adjacent chains are linked by inter-molecular C-H⋯Cl hydrogen bonds, forming a three-dimensional supra-molecular network.

A polymorph of diaqua-bis(pyrazine-2-carboxyl-ato-κN,O)copper(II).

The title compound, [Cu(C(5)H(3)N(2)O(2))(2)(H(2)O)(2)], is a new polymorph of the previously reported compound [Klein et al. (1982 ▶). Inorg. Chem.21, 1891-1897]. The Cu(II) atom, lying on an inversion center, is coordinated by two N atoms and two O atoms from two pyrazine-2-carboxyl-ate ligands and by two water mol-ecules in a distorted octa-hedral geometry with the water mol-ecules occupying the axial sites. Inter-molecular O-H⋯O, O-H⋯N and C-H⋯O hydrogen bonds connect the complex mol-ecules into a two-dimensional layer parallel to (10), whereas the previously reported polymorph exhibits a three-dimensional hydrogen-bonded network.